More than one in every 100 adults in the United States are in jail or prison, an all-time high, according to a new report released last week by the Pew Center on the States. In this report written by Faiza Elmasry (and read by Faith Lapidus) we learn more about the reality behind these numbers.

According to the Pew study, there are more than 2-point-3 million people in U.S. jails and prisons, 25,000 more than there were last year.

"It wasn't always this way," says Adam Gelb, the director of the Public Safety Performance Project and co-author of the new report. "It wasn't until the late 1960s, early 1970s, that the incarceration rate in this country started to creep up."

Gelb says this increase in inmates is not the result of a rise in crime.

"It's really a result of a harsher sentencing policy and stricter release practices," he explains.

The United States, he says, leads the world in both the number and percentage of people it incarcerates.

"China is second in the total number of people behind bars — that they report," he says, "but (they're) far behind in terms of the overall incarceration rate."

Some U.S. states have higher rates of incarceration than others.

"If you look at the map," notes Adam Gelb, "almost straight across the South, from Florida to Georgia to Alabama to Mississippi and Louisiana, over to Texas: these are the states that are incarcerating at the highest rate."

As the prison population expands, Gelb adds, so does its cost. Last year alone, state governments spent more than $49 billion on corrections, up from $11 billion just two decades before. Gelb says five states [Vermont, Michigan, Oregon, Connecticut and Delaware] now spend as much or more on corrections as they do on higher education.

"Because the costs have gotten so high, state lawmakers are taking a second look and evaluating other strategies," he says. "Texas, for example, is hardly a 'soft-on-crime' state, but it's getting 'smart-on-crime.' Rather than building eight new prisons in their last legislative session, (Texas lawmakers) decided to expand a network of residential treatment centers for low-level offenders with drug problems. They figured this will save them hundreds of million of dollars."

But saving money shouldn't come at the expense of public safety, according to Paul Cassell, a Law Professor at the University of Utah and a former judge.

"We could certainly reduce the number of people in prison today by releasing lots of criminals," he says, "but of course, the downside of that would be increased crime rates and increased victimization."

Cassell says the Pew survey of the U.S. prison population considered only half of the equation and overlooked the positive message of the numbers.

"I think the good news is we've seen a reduction in crime rates over the last 20 years," he says. "Crime rates have gone down by 25 percent over the last 20 years. I think the reason for that is we have lots of criminals in prisons. They are not able to victimize people again. That increases the public safety for all law-abiding Americans."

Having a large prison population is a small price to pay, Cassell believes, if it has contributed to a nation-wide increase in public safety.